Encapsulated optical components including wave guides, connector means, etc. connected thereto are generally used within the field of optical communication, in which signals are transmitted mostly by means of optical fibers. In order to expand the use of optical transmission of signals it would be advantageous if components and connectors could be manufactured at lower costs and that the costs for mounting them could be reduced. One of the most important reasons for the high costs of such components is the extreme mechanical precision required when aligning an optoelectrical component with a wave guide such as an optical fiber and when aligning a wave guide in a component with another wave guide.
Thus, plastic capsules containing optoelectrical components and having an integrated optical interface are presently used together with matched connector means coupled to individual optical fibers or to ribbon fibers. The term component is here principally used for a finished product to be mounted on for example a circuit board or similar device and a component is then built of a number of building elements. Optoelectric modules and submodules constitute one type of components.
Optoelectrical commercial components are often provided with a fiber tail or "pigtail", which is an optical fiber extending from the interior of the component and having a free length outside the component. Thus, the fiber tail has one of its ends located inside the component and at this inner end usually an interface to some optoelectrical circuit or to a lens is provided. At the other end of the fiber tail, at the free or exterior end thereof, often some optical connector is mounted.
Such a fiber tail, i.e. a piece of an optical fiber, which at one of its ends is to be in contact with an optoelectrical circuit and which at its other end possibly already has a mounted optical connector, generally constitutes a significant obstacle in the case where one wants to manufacture modules or submodules in a cost-efficient way. This obstacle comprises that the optical fiber tail in a purely physical manner is hindering in automated production, what can result in disturbances of the production. In an encapsulating process in an injection moulding machine, when an encapsulating plastics material is moulded to enclose the optoelectrical circuit together with the inner portion of the fiber tail and when thereafter a curing operation of the plastics material is to be executed, there is a risk of obtaining damages to the polymer coating or sleeve of the optical fiber owing to the high temperatures used. Furthermore, equipment designed for automated production, such as machines for automatic mounting of circuits on circuit boards, will owing to their more complex design have a higher price in the case, where such equipment also is to handle circuits having projecting fiber tails.
The published European patent application EP-A-2 0 125 499 and U.S. Pat. No. 5,452,390 disclose connectors for optical fibers comprising ferrules, in which the fiber ends are pressed against each other for establishing contact between the ends. The pressing force is partly produced by springs of various types which for example act on one of the ferrules and press it towards the other ferrule. In the cited U.S. patent a slotted, resilient sleeve or tube is used for aligning the ferrules with each other.
U.S. Pat. No. 5,617,495 discloses a connection structure for an optical device having a ferrule extending from a package. Around the ferrule a fastening block may be provided having cleat portions arranged to cooperate with flange portions of a bent plate spring. When connecting the device the spring is pressed downwards to engage the fastening block. An optical fiber connector assembly is disclosed in U.S. Pat. No. 5,195,156 using a pin cooperating with a locking slot for securing the two parts of the assembly to each other.